Refrigeration



P D. G. SMELLIE 2,295,973

REFRIGERATION Filed Au 17, 1939 2 Sheets-Sheet 1 INVENTOR Fly. 1 Donald 61.6mellie ATTORNEY Sept. 15, 1942.

D. G. SMELLIE REFRIGERATION Filed Aug.

2 sheets-sheet 2 2 4 4 5 W. 5 III fil'l/ll,flllllll i/f/lllllllllll 8 l 4 m 5 V 3 W 7 n 8 5 Q5 5 5 4 9 V J 3 6 H A t 4 l w i n I. 0 6 6 n H 0 9 H .9 5 H 6 III/IIII/IIIIIIIIII/IIIIIIIIII/IIIII/IIIII/I/l/ 29 Y Donald G. smelli 9 ATTORNEY inoperative the greater Patented se s- 15,1942

V ITED PA T OFFICE REFRIGERATION Donald G.

Smellie, Canton,

The Hoover Company, Application August 17, 1939, Serial No. 290,577 18 Claims. (Cl. 62-5) The invention relates to the art of refrigeration and more particularly to a novel absorption refrigerating apparatus of the three-fluid type so constructed and arranged that the system automatically and'instantaneou'sly adjusts itself to variations. in operating conditions.

' and represents a direct waste of the heat supplied to vaporize the same in the generator. attempts in the past have this difliculty by incorporating within the system Various been made'to overcome various pieces of apparatus which in effect 1 change the charge of the system. However, these devices are not altogether functionally satisfactory and they represent a very appreciable increase in the cost of the apparatus and in the bulk thereof as well as requiring the pro-' vision of a quantity oi operating fluid which is part of the time. I Accordingly, it is a principal object of the present invention to provide an absorption refrigerating system of the. three-fluid type in which variations in operating conditions are compensated by the system to.

automatically maintain the operating emciency and characteristics thereof without the provision of cumber some and expensive auxiliary apparatus and aithout altering the effective charge'in the sysair-cooled rectifier Ohio, assignor to North Canton, Ohio ance with variations in the temperature of the cooling air flowing across the absorber and condenser in order to maintain the operating characteristics of the temperatures.

It is a still further object of the present invention to provide a three-fluid absorption refrigerating apparatus including means which will vary the rate of circulation of the lean inert gas and of the absorption solution in conformity with variations in the refrigerant vapor concentration of the lean inert gas induced by alterations in operating conditions.

Other and further objects of the invention will become apparent as the drawings in which:

Figure 1 is a diagrammatic representation of a three-fluid absorpt on refrigerating system embodying the present vention.

Figure 2 isa schemmatic detail wiring diagram on an enlarged scale of the control device associated with the invention of Figure 1.

Figure 3 is a diagrammatic representation of a modified form of the invention.

Figure 4. is a partial sectional detail view on an enlarged scale of a portion of the apparatus included in Figure 3.

Referring now to the drawing in detail andfirst to Figures 1 and 2 thereof, there is disclosed a continuous three-fluid absorption refrigerating system embodying a boiler B, an analyzer D, an

R, a tubular air-cooled condenser C, an evaporator E, a gas heat exchanger G, a liquid heat exchanger L, a solution reservoir 8, an inclined tubular air-cooled absorber It is a principal object of the present invention to provide a three-fluid absorption refrigerating apparatus sot the rate at which the absorptionsolution and inert gas are circulated varies directly and proportionately to a controlling operating condition to maintain desirable operating characteristics under all conditions. v

It he still further object of the present invention to provide a three-fluid absorptionrefrigerating system so constructed and arranged that the effective flow producing pressure diflerential' in the inert gas circuit and the effective pressure of the pumping gas supplied to the solution A, and a circulating fan F which is driven by a suitable electrical motor M. The above described elements are interconnected by various conduits to provide a plurality of gas and liquid circuits constituting a complete refrigerating system to which reference will be made in more detail constructed and arranged circulating pump are varied directly in accord- 5 preferably a dense hereinafter.

The above described refrigerating system will be charged with a suitable refrigerant, such as ammonia, a" suitable water, and an inert inert gas, like nitrogen. The boiler B is heated in any desired or preferred manner. As

urner H, to which reference will be made in more detail hereinafter, is provided.

The application of heat to the boiler'B generates refrigerant vapor from the refrigerant absorbent solution therein contained. The vapor system with variable room description proceeds when taken in connection with the accompanying absorbent therefor, such as pressure equalizing medium,

illustrated, a combustible fuel cludes a downwardly extending U-shaped portion designed to form a pressure balancing liq- .uid column to maintain a pressure differential between the evaporator and the condenser. The upper portion of the condenser side of the conduit I3 is vented to the rich gas side of the gas heat exchanger G by means of a conduit It. Due to the high gas flow resistance of the evaporator the pressure within the rich gas side of the gas heat exchanger G is appreciably below that prevailing at the point in which the liquid refrigerant is supplied to the evaporator wherefore a pressure balancing column is formed in the conduit i3.

The liquid refrigerant which is supplied to the bottom portion of the evaporator E meets a propelled stream of lean inert gas which is supplied to the evaporator from the circulating fan F by way of the conduit IS, the gas heat exchanger G and the conduit IT.

It is preferred to use an evaporator of the type in which the inert gas circulates with a velocity suflicient to sweep or drag the liquid refrigerant therethrough as it is evaporating to produce the refrigerating effect. In the evaporator illustrated there is also provided an upper enlarged diameter flnned box-cooling conduit it through which the liquid refrigerant may flow by gravity if desired.

The evaporator has been illustrated herein only diagrammatically, A preferred detail construction of evaporator is disclosed and claimed in the co-pending application of Curtis C. Coons and William H. Kitto, Serial No. 386,395, filed April 2nd, 1941, which is a continuation-in-part of application Serial No. 220,189, filed July 20th, 1938. However, it is to be understood that various other forms of evaporators may be utilized with the present invention, for example, the conventional gravity flow type- 1 The rich gas formed in the evaporator E is conveyed therefrom to the bottom portion of the absorber 'A by way of the conduit 28, the gas heat exchanger G, and a conduit 24. The rich gas flows upwardly through the absorber A in counterflow relationship with lean absorption solution flowing downwardly therethrough and in intimate contact with such solution. The manner in which the solution is supplied to the absorber will be described in detail hereinafter. The absorption solution absorbs refrigerant vapor from the inert gas refrigerant vapor mixture supplied through the conduit 2i, and the resulting heat of absorption is rejected to the cooling air flowing over the exterior walls of the absorber and the air-cooling fins mounted thereon. The lean gas formed in the absorber is conveyed from the upper portion thereof to the suction inlet of the circulating fan F by way of the conduit 22, thus completing the inert gas circuit.

The lean solution produced in the boiler B by the generation of refrigerant vapor is conveyed therefrom to the solution reservoir S by way of the conduit 25, the liquid heat exchanger L, and a looped finned solution pre-cooling conduit 28. The reservoir S is vented by means of a conduit 21 to the suction conduit 22 of the circulating fan F whereby the liquid level in the reservoir S is substantially stabilized and the liquid level in the reservoir S is higher than that prevailing in the boiler-analyzer system by an amount sufflcient to balance the pressure differential between the conduit 22 to which the reservoir is vented and the upper rich gas portion of the gas heat exchanger G to which the boiler-analyzer condenser system is vented by way of the conduit It.

The lean solution is conveyed from thereservoir S into the suction conduit 22 adjacent its point of connection to the upper portion of the absorber A by means of a gas lift pumping conduit 28. Pumping gas is supplied to the conduit 28 below the liquid level normally prevailing therein by means of a conduit 29 which is connected to the discharge conduit it of the circulating fan F.

The lean solution supplied to the conduit 22 flows downwardly through the absorber A by gravity in counterflow relationship with the pressure equalizing refrigerant vapor mixture flowing upwardly therethrough. The rich solution produced in the absorber is conveyed from the bottom portion thereof to the upper portion of the analyzer D by means of the conduit 3!, the liquid heat exchanger L, and the conduit 32. This completes the absorption solution circuit.

The heater H for the boiler B is supplied with fuel by means of a conduit 35 which includes a solenoid control valve 36 of the type normally urged to closed position. A by-pass 31 is provided around the valve 36 in order to maintain a small pilot or igniting flame on'the burner H which will include suitable safety cut-ofi mechanism (not shown) of a type to discontinue the supply of fuel thereto completely upon the total failure of the flame.

The apparatus is controlled by means of a suitelement M which may be positioned to respond to the temperature of the space to be refrigerated or to the temperature of the evaporator in the manner shown. The mechanism 40 may be of any desired or conventional type and is well known, consisting principally of a thermostatically controlled switch and a mechanism for adjustingits control point. Electrical energy is supplied to the mechanism M3 by means of electrical supply lines 42. The mechanism to exercises direct control over the solenoid valve 38 to which it is connected by the electrical conductors 53.

The control mechanism 40 also controls the energization of supply lines M which lead to an auxiliary motor control mechanism indicated generally at $5 in Figure 1.

The motor control mechanism is provided with a pressure sensitive thermostatic bellows :38 which is actuated in response to the temperature of the cooling air flowing over the absorber and condenser by means of a capillary conduit 49 which carries a finned bulb element 50 on its end portion whereby the bellows 48 expands and contractsin response to variations in the temperature of the cooling air.

, One end of the bellows 48 is rigidly mounted portion in position to site ends of the windings ductor 65 then connects in the cable 44.

' desired.

on a casing element by means of a nut 52.

' The other end of the bellows 48 is provided with an extending shaft 53 provided with a reduced diameter slot 54 adjacent its end portion. The

mechanism which is order to actuate the same.

The free arm 56 of the toggle mechanism carries electrical conductor plates 51 on itsfree end contact electrical contactors 58 and .59 which are positioned on the right and left hand sides thereof respectively, as viewed in Figure 2, and in'spaced relationship.

The motor M is provided with two windings so and 6| which are 4 and 6-pole windings, respectively. These windings are shown schematically in Figure 2 and will be arranged in a knciwn manner in the motor. of the induction type in which a sealing shell is provided between the stator windings and the rotor in order to seal the refrigerating systemand to prevent the contents thereof from coming in contact'with the stator windings;

The motor is preferably I tion circulation is determined by the depth of The electrical contact 59 is connected to one end of the 4-pole winding 60 by means of a conductor 63 and the electrical contact 58 isconnected to one end of the 6-pole winding 6| by means of an electrical conductor 64. The oppo- 60 and 6| are connected conductor 65. The condirectly to a supply wire 66, the energization of which is controlled bythe main control mechanism 40. It will be under togetherby means of a stood that the conductor 66 will be housed within the cable 44 connecting the control elements and 45. The movable arm 56 of the toggle mechanism is supplied with electrical current through a conductor 61 the control mechanism 40 and is included with- As is shown in Figure .1, the various electrical connections between the control mechanism and the motor M are housed withina suitable cable 168.

The above described refrigerating system will be associated in the usual manner with an inl sulated cabinet preferably of the type which is provided with a'rear cooling fine in which the condenser is housed and a lower mechanism compartment in which the absorber is housed.

The bulb which is designed to respond to the temperature of the cooling air supplied to the absorber may be positioned in the mechanism compartment directly beneath the absorber in which event it will respond to the temperature of the cooling air before it traverses the absorber, or it may be positioned in the rear aircooling flue in which event it will respond to the temperature of the. cooling air which has traversed the absorber. In either event suitable calibration of the bellows 48 will be provided to assure proper operation of the system.

An induction motor provided with 4 and G-pole windings energized fromv -cycle alternating current will have synchronous speeds of 1800 R. P. M. and 1200 R. P. M., respectively. Such a motor will have operating speeds of approximately 1700 R. P. M. and 1130 R. P. M., respectively. However, if it is desired to decrease the speed differential the motor can be designed to have much greaterv slip when operating with 4-poles, for example, to bring the actual 4-pole running speed. d

The operation of this form of the inventionis as follows: Assuming .that there is a demand for Wu" as low as 1500 B P. M. if 3 refrigeration and thatf'atmospheric temperature conditions are relatively low, for example, approximately in the neighborhood 0f-70 F., the control mechanism will energize the heater for the boiler B and will energize the supply connections to the motor control 45. At low room temperatures the bellows 48 will have contracted and will have actuated the toggle mechanism to immersion ofthe pump which is fixed by the quantityof solution in the apparatus and the relative positions of the various parts thereof. Therefore, the rate at which the inert gas circulates is designed to provide adequate solution circulation, adequate inert gas circulation and adequate distribution of the liquid refrigerant in the evaporator at the low, or'6-pole speed of the circulating motor and its associated fan.

As the room temperature gradually increases the operating temperature of the absorber increases correspondingly as the absorber must reject its heat to the cooling air flowing thereover. An increase in the temperature of the cooling air supplied by the conduit which also connects to higher temperature w "ch decreases its ability to absorb the refrigerant vapor from the mixture 2|. As a result of the decreased efliciency of the absorber the lean gas which is returned to the evaporator contains a. higher concentration of refrigerant vapor which decreases by so much the ability of the inert gas in the evaporator to promote evaporation of the liquid refrigerant supplied to the condenser. appropriate steps are not taken this phenomena will 'go on progressively until the capacity of the system is seriously impaired.

The present invention overcomes this difliculty by stepping up the motor speed as the room temperature approaches a high value, say for example F. This is accomplished as follows: When the room temperature passes the 90 mark, the bellows 48 expands in response thereto and actuates the toggle mechanism 55 to the left, as

viewed in Figure 2, to de-energize the 6-pole circulating fan F will circulate the inert gas at pressure a greater velocity due to the greater differential produced thereby.

Since the gas lift pumping mechanism comprising the conduits 28 and 29 are connected directly across the circulating fan F, this increase in the discharge pressure of the fanresults in an increase in the pressure of the gas supplied to the conduit 29 and consequently an increase in the rate of circulation of the absorption solution.

Since the absorption solution is now circulating at a greater rate circulating .at a higher rate the absorber is now able to maintain the concentration of refrigerant vapor in the lean gas within desired limits even at the high temperatures at which it is operating. This results partly from the fact that there and since the inert gas is also is now a greater quantity of absorption solution available in the absorber per unit of time to allsorb the refrigerant vapor picked up by the inert gas in the evaporator per unit of time. Also the concentration of the rich gas which is returned from the evaporator to the absorber is somewhat reduced because of the greater quantity of inert gas circulating through the evaporator and the increased flow of the solution and increased velocity of the inert gas from the absorber results in greater turbulence in the fluids therein and in improved scrubbing action of the same along the walls oi the absorber which improves the hwt rej ection and absorption.

Consequently, the present form of the invention provides a construction whereby the rate of circulation of the fluids in the apparatus are automatically stepped up as an operating condition of the apparatus changes, the room temperature increases. in order to maintain the operating eharacteristicsof the system and the proper balance between the concentration in the various fluids found i various parts thereof.

Referring now to Figures 3 and 4 there is disclosed a modified form of the invention. Since this form of the invention differs irom that previously described in connection with Figures 1 and 2 only in the construction of the absorption solution circuit, only that part of the apparatus has been. illustrated, it being understood that the other parts are identical with that disclosed in connection with Figures 1 and 2. Certain elements of the apparatus disclosed in Figures 2 and 3 are identical with apparatus described and illustrated in connection with Figures 1 and 2 and are therefore given the same reference characters primed.

In this form of the invention, however, the circulatingfan F isdriven by an electrical motor it which has but a single operating speed.

In this form of, the invention the circulating motor ill and the heater for the boiler B, which may be identical with that disclosed in connection the conduit l6 beyond its 'point of connection with the by-pass i and hence the effective pressure in the conduit 29'.

The thermostat :11 does not respond directly to the temperature of the cooling air flowing over the absorber A but to the temperature of the lean gas flowing through the sleeve I3. However, the lean gas temperature is a direct Iunctlon of the temperature of the cooling air and appropriate calibration of the thermostat I1 is readily accomplished.

Now assuming that the temperature of the cooling air gradually increases, the temperature of the lean gases flowing through the sleeve 73 will also gradually increase and will afiect the thermostat Ti to cause the same to flex to the right,,

' .quantityoi inert gas which is circulating in the with Figures 1 and 2 or which may be of any other preferred and desired type, will be directly under the control of a control mechanism such as that disclosed at to in connection with Fig- .ures 1 and 2.

In this form of the invention, however, the conduit 22 connecting the upper portion of the absorber to the suction side of the circulating fan has been replaced by a pair of spaced conduits H and it connected by a control valve casing and sleeve l3. Thevent conduit 27' lfrom the reservoir S and the gas lift pumping conduit 28' each connect to the conduit H which connects directly to the upper portion of the absorber A".

as follows: When, the room temperature is say 70. or below, the thermostat 11 will have shifted the valve plug 18- to the left, as viewed in Figure 4, to provide free communication between the by inert gas circuit proper will gradually increase as will the pressure of the pumping gas supplied to thepumping conduit 2&3 by the conduit 29.. Consequently the rate of inert gas circulation and the rate of absorption solution circulation gradually increases with increasing atmospheric temperature conditions to compensate the appsratus for the same to maintain proper concentration of the inert gas supplied to the evaporator and to provide an adequate quantity of absorption solution per unit oftime to the ab-' soldier to insure that the refrigerant vapor picked up in the evaporatorper unit of time will 1 be efficiently absorbed in the solution and returned to the boiler for further vaporization. Therefore, in this form of the invention the rate of solution circulation and the effective rate of inert gas circulation is varied infinitely between a low temperature and a high temperature condition as determined by operating conditions of the apparatus to maintain normal operating conditions therein.

In each form of the invention herein disclosed means are provided for varying the rate of inert gas circulation and the, rate of solution circulation in a three-fluid absorption refrigerating apparatus to maintain efiicient operating conditions thereof under varying conditions of cooling air temperature and without altering'the eflective charge of the system in any way.

While the invention has been illustrated and described herein in considerable detail, various changes may be made in the form, construction and arrangement of part; without departing from pass conduit I5 and the interior" of the valve sleeve 13, thus appreciably reducing the effective quantity of. inert gas circulating through the inert gas circult and the eifective pressure in.

the spirit of the invention or the scope of the ap I pended claims.

I claim: l 1. Absorption refrigerating apparatus comprising an inert gas circuit including an (W890.-

rator and an absorber, a solution circuit including a generator and said absorber, means for liqueiying refrigerant vapor produced in said generator and for supplying the liquid to said evaporator, a gas lift conduit included in said solution circuit for circulating the solution, means for supplying pumping gas from said inert gas circuit to said gas liit conduit to operate the same, and means for varying the pressure of the gas supplied to said gas lift conduit in response to changes in acondition affecting the operation oi. the apparatus. Y

generator and for supplying the liquid ,to said evaporator, a as lift conduit included in said solution circuit for circulating thesolution,-

means for supplying pumping gas from said inert gas circuit to said gas lift conduit to operate the same, means for producing a pressure differential in said inert gas circuit to cause circulation of the inert gas, and means responsive to the ambient temperature for changing the effective inen't gas flow producing pressure differential whereby to alter the rate of inert gas and solution circulation;

3. Absorption refrigerating apparatus comprising an inert gas circuit including an evaporator and an air-cooled'absorber, a solution circuit including a generator and said absorber, means for liquefying refrigerant vapor produced in said generator and for supplying the liquid to said evaporator, a gas lift conduit included in said solution circuit for circulating the solution, means for supplying pumping gas from said inert gas circuit to said gas lift conduit to operate the same, and means responsive to the temperature of the cooling air supplied to the absorber for regulating the rates of solution and inert gas u circulation.

4. Absorption refrigerating apparatus comprising an inert gas circuit including an evaporator and an air-cooled absorber, a. solution circuit including a generator and said absorber, meansfor liquefying refrigerant vapor produced in said generator andfor supplying the liquid'to said evaporator, a gas lift conduit included in said solution circuit for circulating the solution,

means for supplying pumping gas from said inert gas circuit to said gas lift conduit to operate the same, power driven means for propelling the generator and said absorber, means for liquefying refrigerant vapor produced in said generator and for supplying the liquid to said evaporator, a gas circulating the solution, means for supplying pumping gas from said inert gas circuit to said gas lift conduit to operate the same, a power driven inert gas circulator in said inert gas circuit, and means responsive to a thermal condition affecting normal operation of the system: for varying the capacity. of said circulator in response to changes in such thermal condition.

6. Absorption refrigerating apparatus comprising an inert gas circuit including an evaporator and an air cooled absorber, a solution circuit including a generator and said absorber, means for liquefying refrigerant vapor produced in said generator and for supplying the liquid to said 1 evaporator, a gaslift conduit included in said solution circuit for circulating the solution, means l inert gas through said inert gas circuit, said gas t for supplying pumping gas from said inert gas circuit tov said gas lift conduit to operate the same, a' power driven inert gas circulator in said inert gas circuit, a by-pass around said inert gas circulator, and means responsive to a thermal condition affecting the operation of the system for varying the effective capacity of said bypass in accordance with such condition.

7. Absorption refrigerating apparatus comprising an inert gas circuit including an evaporator and an air-cooled absorber, a solution circuit including a generator and said absorber, means for liquefying refrigerant vapor produced in said generator and for supplying the liquid to'said evaporator, a gas lift conduit included in said solution circuit for circulating the solution, means for supplying pumping gas from said inert gas circuit to said gas lift conduit to operate the same, a motor driven circulating fan in said inert gas circuit, said motor having a plurality of windings having different operatingcharacteristics, means for heating said generator, means responsive to the temperature of the cooling air for conditioning a selected one of said motor windingsffor energization in accordance with such temperature, and refrigeration demand responsive means for governing the operation of said heater and the energization of said selected winding.

8. Absorption refrigerating apparatus comprising an inert gas circuit including an evaporator and an absorber, a solution circuit including a generator and said absorber, means for liquefying refrigerant vapor produced in said generator and for supplying the liquid to said evaporator, a gas lift conduit included in circulating the solution, means for supplying pumping gas from said inert gas circuit to said gas lift conduit to operate the same, a power driven inert gas circulator in said inert gas circuit, a by-pass around said inert gas circulator, a throttling valve in said by-pass and a thermostat arranged to be responsive to .the temperature of e lean gas leaving said absorber for actuating said throttling valve to decrease the gas flow lift conduit included in said solution circuit for through said by-pass as the temperature of such lean gas rises, I

9. That improvement in the art of refrigerating systems of the type utilizing a refrigerant, an absorbent therefor and a pressure equalizing medium inert with respect to the refrigerant and absorbent which includes the steps of expellin refrigerant vapor from solution in the absorbent by the application of heat thereto, liquefying the vapor so produced, evaporating the liquid into a moving stream of the pressure equalizing madium, absorbing the refrigerant vapor from the refrigerant vapor pressure equalizing medium mixture by contacting the same with a stream of absorbent solution previously weakened by the expulsion of refrigerant vapor therefrom, and regulating the relative proportions of absorption.

solution and of pressure equalizing mediumbrought into contact with the refrigerant vapor pressure equalizing medium mixture and the liquid refrigerant per unit of time respectively in accordance with a condition affecting the operarefrigerant vapor from solution in the absorbent by the application of heat thereto, liquefying the vapor so produced, evaporating the liquid into a said solution circuit for pressure equalizing me-' body of pressure equalizing medium circulating between evaporating and absorbing zones, circulating absorbing solution through the absorb ing zone by diverting pressure equalizing medium under pressure from the circulating body of pressure equalizing medium and introducing it into an upstanding body of absorbent solution, and regulating the operating characteristics of the pressure equalizing medium and of the absorbent solution in accordance with ambient temperature.

1l.- That improvement in the art of refrigerating systems of the type utilizing a refrigerant, an

absorbent therefor and a pressure equalizing medium inert with respect to the refrigerant and absorbent which includes'the steps of expelling refrigerant vapor from solution in the absorbent in a generating zone by the application of heat thereto, liquefying the vapor so'produced, circulating the pressure equal'ming medium between evaporating and absorbing zones by creating a flow producing pressure differential in a localized I area of the system containing pressure equalizing medium, circulating the absorbing solution between the generating and absorbing zones by subjecting the solution to the circulating action of pressure equalizing medium in a localized area of the system containing absorbing solution, rejecting the heat of absorption to the surrounding air, and governing the operation of the system by altering the effective flow producing value of said pressure difierential in response to changes in air temperature.

12. Absorption refrigerating apparatus of the three-fluid type including a boiler, an absorber.

' a condenser and an evaporator connected in circult, power driven means for circulating inert as and absorbing solution in said apparatus, and means responsive to the heat rejecting capacity oi said absorber and condenser for governing the rates of inert gas and absorbing solution circulation in accord therewith.

l3. Absorption refrigerating apparatus of the three-fluid type including a boiler, an air-cooled absorber, a condenser and an evaporator connected in circuit, power driven means for circulating an inert gas through said evaporator and said absorber, a circulating pump for circulating an absorbing solution between said boiler and said absorber, and means responsive to coolin air temperature for regulating the rates of cirsystem by altering the rates of circulation of the aeeaove culation of said inert gas and said absorption solution.

14. Absorption refrigerating apparatus comprising an inert gas circuit including an evaporator and an absorber, a solution circuit including a generator and said absorber, means for liquefying refrigerant vapor produced in said generator and for supplying the liquid to said evaporator, means in said inert gas circuit for creating a gas flow producing pressure difierential in a local area thereof, and means for by-passins inert gas around said pressure differential flow producing means in response to changes in a condition afiecting the operation of the apparatus to compensate the apparatus for changing conditions.

15. Absorption refrigerating apparatus comprising an inert gas circuit including an evaporator and an absorber, a solution circuit includ ing a generator and said absorber, means for liquefying refrigerant vapor produced in said gen- 'erator and for supplying the liquid to said evaporator, a power operated inert gas circulating means in said. inert gas circuit, a by-pass in said inert gas circuit around said power'operated circulator, and thermostatic means arranged to vary the flow capacity of said by-pass in response to a thermal condition affecting the operation of the apparatus.

16. Absorption refrigerating apparatus comprising an inert gas circuit including an evaporator and an air-cooled absorber, a solution circuit including a generator and said absorber, means for liquefying refrigerant vapor produced in said generator and for supplying the liquid to said evaporator, a gas lift conduit included in said solution circuit for circulating the solution, means for supplying pumping gas from said inert gas circuit to said gas lift conduit to operate the same, means in said inert gas circuit for creating a pressure difierential therein suflicient to operate said gas lift and to circulate the inert gas through said evaporator with sumcient velocity and pressure to circulate the liquid refrigerant in said evaporator by the frictional dragging action or the inert gas flowing in contact with the liquid refrigerant, and means for varying the pressure of the gas supplied to said gas lift conduit in response to changes in a conditlon afiecting the operation of the apparatus.

DONALD G. SMELLIE. 

